Pretreated sealed parquet plate



Gct. 27, 1.970 J. STRBING v3,=,35,839

PRETREATED SEALED PARQUET PLATE Filed May 29, 1968 s sheets-sheet 1 V-mFig1 F192 Oct. 27, 1970 J. s-rRUBlNG 3,535,839

y PRETREATED SEALED PARQUET PLATE Filed May 29, 1968 3 Sheets-Sheet 2INVENTOR, Jaarw/M freue/m6 Oct. 27, 1970 J. sTRUBlNG 3,535,839

PRETREATED SEALED PARQUET PLATE Filed May 29,1968 3 Sheets-Sheet 3 YFig. 11 Fig. 12

United States Patent U.S. Cl. 52-99 1 Claim ABSTRACT 0F THE DISCLOSURE Aparquet flooring plate or unit is composed of elementary elongate Woodenstrips arranged in square-shaped groups, and a plurality of such groupsare joined to form a rectangular parquet unit in which the individualstrips and the different square-shaped groups are held together prior tolaying the floor by elastically extensible tapes glued to the undersideof the assembled unit. The units have their top face ground and sealedin the factory prior to laying the oor. After sealing, the continuoussealing agent layer on the top face of the unit is broken across alljoints between adjacent elementary strips in the unit by bending thestrips relatively to each other to subject the sealing agent layer abovesaid joints to tensile stress, while said extensible tapes on theunderside are yielding and remain intact.

The invention relates to sealed parquet plates, ready to be laid on afloor and composed of individual small wooden blocks or strips joinedtogether to form a parquet panel.

lParquet plates which are composed of such strips, particularlyso-called mosaic parquet panels in which the strips are joinedcheckerboardlike with crossed direction of grain are provided on theunderside with a bond consisting of narrow paper or fabric strips inorder to maintain the individual wooden Iblocks or strips in assembledcondition. These bonding strips are applied flat to the underside of thepanels or are sunk for about one half millimetre into the bottom face ofthe panel, whereby the thickness olf the wooden blocks or strips issubstantially conserved as useful thickness. The plates or panels arelaid on a subiioor by the aid of normal aqueous dispersion adhesives,usually PVA adhesive. For sealing the parquet flooring, normal varnishis used.

It is no difficult problem, to lay mosaic parquet plates with hydrousadhesive. The individual blocks or strips slightly swell at theunderside when the panels are laid into the adhesive layer. Thedeformations, however, are small and are removed when the flooringsubsequently is ground, if they did not disappear already bycompensation of the moisture content. Also subsequent sealing of thelaid flooring does not offer any difficulties. The stresses exerted bythe drying and setting sealing layer are insignicant as compared withthe stresses which can be absorbed by the adhesive.

Difficulties, however, will be experienced when the parquet panels areground and sealed in the parquet manufacturing plant, thus prior tobeing laid to a floor. When already sealed parquet panels are laid,these panels are no longer loose articulated units of individual parquetblocks or strips, but stiff and rigid wooden plates have to be laid,since obviously all individual wooden blocks or strips of the sealedplates are rigidly connected to each other by the sealing varnishtransversely to the direction of grain. This rigid bonding of theindividual wooden strips is not desired, however, it cannot be avoided,since the sealing layer forms a iilm which bridges the joints betweenthe i ce strips and also penetrates into the joints and causes theadjacent blocks or strips to become glued to each other.

When such a rigid parquet panel of a width which is many times largerthan the width of an individual block or strip, is moistened on itsunderside upon being laid into the layer of adhesive, the swelling anddeformation have a very much increased effect, since as is well known,the height of arc or deflection of a segment of a circle increases withthe square of its length. Flooring surfaces having such concave,deformed parquet plates have not only a poor appearance but aretechnically inadequate, since the deformed plates are only bonded hereand there at certain points to the subfloor.

Different means have already been used to eliminate these undesiredeffects, which until now prevented an efficient use of parquet panelssealed in the factory prior to laying on the floor. It is possible touse dehydrated adhesives for laying a lioor. Such adhesives, however,have technical disadvantages; they often are harmful to health andinammable and have the tendency of aging and becoming brittle.

Another possibility of avoiding the deformation of parquet panels sealedprior to laying is the covering of the underside of the panels, i.e., toprotect the panels against the water in the adhesive. For example,bituminated paper can be glued to the underside of the panels. Such anintermediate layer, however, can impair the bonding of the parquetpanels with the subfloor and render the lloor inapt for use. Continuouscarrier layers or protecting layers having improved stability propertieshave also been used, but such additional layers are expensive and resultin other drawbacks.

It is also possible to modify the composition of the sealing agents inorder to avoid the sticking together of the joints between theelementary parquet strips or blocks, which is principally responsiblefor all difficulties encountered. When a sealing varnish is used havinga very low content of solid bodies, and moreover the varnish is appliedin a quite thin layer, the parquet strips or blocks treated with such avarnish stick only slightly together when the correct applicationprocedure is used, so that the feared deformation of the panels does notoccur. The sealing quality obtained by such agents, however, isdeficient and poorly sealed parquet plates are unfit for use.

Also, the individual elementary parquet blocks or strips could be sealedrst and then assembled to form panels. This procedure, however, is notsuitable, since practically it is not possible to align the parquetblocks or strips without formation of disturbing lippings betweenadjacent strips, apart from a higher consumption of sealing agent.

It is an object of the present invention to provide a parquet platewhich avoids the above mentioned drawbacks.

According to the invention bonding means of extensible and iiexiblematerial are applied to the underside of the joined elementary parquetblocks or strips to hold them together prior to laying of the plates,the extensibility of said bonding means being at least twice as high asthe extensibility of the sealing agent layer on the top side of thejoined elementary blocks or strips, and the sealing agent layer beingbroken across all joints between adjacent elementary blocks or strips ofthe plate.

In mosaic parquet plates, in which the individual parquet blocks orstrips are joined to form square elements and these latter are in turnjoined checkerboardlike with crossed direction of grain to form a plate,the bonding means for the blocks or strips applied to the underside ofthe parquet plate conveniently consist of extensible tapes which extendacross the joints -between the blocks or strips and along the marginalportions of said square elements.

The bonding means on the undersides of the plates can be formed also byadhesive coated threads or strings placed into grooves provided on theunderside at the front ends of the blocks or strips and along the jointsof adjacent square elements.

Preferably, the bonding means at the underside of the plates are gluedby application of heat.

The invention also relates to a method for producing such sealed parquetplates ready for laying. This method comprises joining a number ofelongated parquet blocks or strips, applying bonding means of extensibleand flexible material to one side of said blocks or strips across thejoints thereof for holding the blocks or strips in assembled relation,grinding and sealing the other side of the assembled blocks and strips,so as to form on said other side a layer of sealing agent continuouslyextending over the entire surface area of the assembled blocks orstrips, and then breaking said sealing agent layer at the joints betweensaid elementary blocks or strips by bending the blocks or stripsrelative to each other.

The invention will now be described with reference t the accompanyingdrawings in which,

FIG. l is a plan view on the underside of a parquet plate according tothe invention,

FIG. la is an end view of the parquet plate of FIG. 1, viewed in thedirection of arrows 1a in FIG. l;

FIGS. 2 to 10 serve to explain the method of production of a parquetplate ready for laying,

FIGS. l1 and 12 are top plan views of parquet plates according to theinvention having a modified arrangement of the elementary blocks orstrips.

FIG. 1 is a view of the underside of a parquet plate 1 assembled from aplurality of similar elementary wooden strips 2. A number of five strips2, in the represented example, form rectangular or square groups, whichare assembled checkerboardlike with crossed grain to form a plate. Inorder to hold the strips 2 in assembled relation prior to laying theplates to a floor, tapes 3 of an extensible and flexible material suchas paper or plastic, coated or reinforced paper, are glued to the strips2 at the underside of the plate, preferably by means of an elastic orextensible adhesive or by means of an adhesive which has been treated,for example heated to be temporarily elastic. Such a tape 3 extendsalong each of the four marginal portions of the plate transverselyacross the strips 2 of one group and along the outer strip 2 of theadjacent group of strips, and two further strips 2 extend along the twomedian lines of the plate to connect the ends of the strips 2 of onegroup with the longitudinal edge of the first strip of the adjacentgroup. The surface of the parquet plate may be grooved, as shown in FIG.la, to receive the tapes 3 at the locations described just above. Thisnarrow connecting tape 3 suffices to hold the strips 2 together prior tolaying the plates on a floor. The comparatively large Wood surface of aplate permits an effective bonding of the plate with the subfloor, sothat the strength of interconnection of the individual strips by meansof the tapes 3 is of secondary importance and uneveness between adjacentplates or formation of so-called lippings is not to be feared.

A plate composed in this manner of strips 2 in the factory is thenground and sealed also in the factory by the use of normal orconventional sealing varnish.

The parquet plate represented in FIG. 1 also can be produced in anothermanner. As represented in FIG. 2, a. plurality of parallel strips 2a canbe joined to form a long band 4 and the individualwooden strips 2a aremaintained together by tapes 3a which are glued to the underside of theassembled strips 3a. These tapes consist of the same material as thetapes 3 in FIG. l, i.e., of paper, plastic, or reinforced paper. Such aband 4 is then cut into portions of desired length which are ground andsealed in conventional manner by the use of normal sea1- ing varnish.

The sealing of the parquet bands formed by a certain number of strips 2aresults in the undesired effect that the sealing agent penetrates intothe joints between the adjacent individual strips 2a and causes them tostick together. This bonding together of the strips at the jointssubsequently must be broken up, prior to assembling the sealed lengthsof parquet bands to a parquet plate and before the plate can be laid toform a parquet flooring. This can be effected in simple manner bypassing the band about a convex surface or guide roller 5 as shown inFIG. 3. The sealing agent layer 6 of the -band 4 shall be situated inthe tension zone, thus on the outer or convex side of the band. Whenpassing the band 4 over the surface 5, the strips 2a of the band arebent, the layer of sealing agent 6 at the joints and the varnish Whichhad penetrated at the joints along the longitudinal sides of the strips2a is subjected to tensile stress and is broken, while the tapes 3awhich hold the strips 2a together is not stressed and the band formationof the strips remains intact. From the band of strips 2a in which thestrips still are interconnected by the tapes 3a but no longer sticktogether at the sealed face of the band, square groups of strips 2a aresevered and assembled to form plates according to FIG. 1. Formaintaining these groups of strips together, additional tapes 3 areglued across the joints between the groups. It is also possible toprovide laterally projecting connecting tapes when producing the bands4, which tapes would serve for later connecting the severed groups ofstrips 2a to form a plate.

When the parquet plate has been assembled as described with reference toFIG. 1, i.e., when for example four or sixteen squares formed of strips2 are assembled to form a plate and are held together by means of tapes3 on the underside, and only afterwards the plate as a whole is groundand sealed, it will be obvious that a device according to FIG. 3 can nolonger be used for breaking up of the individual strips stuck togetherby the sealing agent, since each square group of strips is connectedalong at least one end side of the strips with a transversely directedstrip of the adjacent square group. In order to subject the sealingagent layer to tensile strength and break it up by a slight totaldeformation, it is possible to proceed step by step as is showndiagrammatically in FIG. 4. Since the sealing agent layer is brittle,but the connection on the underside of the plates is elasticallyextensible as already mentioned, such deformations are effective in thedesired manner, i.e., the sealing agent layer breaks up, while theconnection of the underside remains intact. When, as shown in FIG. 4,breaking up is effected in two successive steps, the underside moreoveris less stressed than the upper side provided with the sealing agentlayer 6, since the angles o between adjacent inclined strips 2 on theunderside measure only one-half of the angles p at the upper side of twoinclined strips 2. When the tape connections at the underside of theplate are sufficiently extensible, it is possible to effect breaking-upin two steps as shown in FIG. 5.

FIGS. 6, 7 and 8 diagrammatically represent a device for breaking up ofa parquet plate according to the method corresponding to therepresentation of FIG. 5, thus in two steps. Obviously, the device woulddiffer in details but not in principle, when breaking up would beeffected in three steps according to FIG. 4.

FIG. 6 illustrates a portion of a parquet plate. The five parquet strips2 visible with their ends and forming a square group of strips, in FIG.1, are designated by a, b, c, d and e. 3 designates the tape connectionin the underside of the strips, 6 is the sealing agent layer, 7represents a base plate, 8 are fixed ledges of a thickness of about 0.5millimetres and slightly shorter than the parquet strips, i.e., they donot project beyond the edges of the square formed by the parquet strips.A rubber block 9 is disposed above the square group of strips a, b, c, dand e and can be pressed from above against the strips by means of apower press.

The ledges 8 are situated beneath the joints between the strips a and b,c and d and beneath the outer edge of the strip e when the parquet plateis placed into operating position in the device. For breaking up thesealing, the resilient rubber block 9 is lowered and pressed against thestrips. Thereby the square of strips is deformed according to FIG. 7,i.e., it collapses in the spaces between the ledges 8 which act assupport underneath alternate joints. In the joints supported by theledges tensile stress is produced and the sealing agent layer is broken.

In order to breakup the remaining joints which had not been separatedbecause they were not subjected to tensile stress, namely the jointsbetween the strips b and c, d and e,the rubber plate 9 is lifted off andthe parquet plate removed and brought into the device according to FIG.8 and there again the parquet plate is compressed by a rubber block 9.The ledges 8 in this device are displaced for the width of one stripwith respect to the arrangement of FIG. 7.

The described base plate 7 with ledges 8 suices to breakup one squaregroup of strips 2 of a plate 1 according to FIG. 1. As alreadymentioned, the parquet plates to be treated consist of several squaregroups of strips 2, for example of four or sixteen squares. The completeapparatus for breaking up such a plate is designed correspondingly, andcomprises also four or sixteen base plates 7 having ledges 8 and one ormore rubber blocks 9.

A characteristic feature of the method is the limited bending of thestrips as diagrammatically represented in FIGS. 4 and 5. The deviceaccording to FIGS. 6, 7 and 8 is only one of many possible forms ofapparatus for effecting the breaking of the sealing agent layer. Insteadof using a rubber block 9, for example a rigid pressing plate could beused which would be provided with ledges such as the ledges 8 of thelower base plate, but which would be displaced for the width of onestrip 2 with respect to the ledges 8, in order to obtain an alternatebending of the strips.

It is also possible to provide the upper plate 10 with ledges 11, asrepresented in FIG. 9. FIG. l illustrates the manner of operation ofthis breaking-up device.

It is possible, instead of the xed supporting ledges 8, to usevertically movable ledges which can be sunk into the base plate, andwhich would be arranged opposite the joints between the strips a and b,b and c, c and d, d and e, and at the end of the strip e and toalternately cause those ledges to project out of the base plate, whichwill be used for effecting the deformation and breaking up of the groupof strips. In this manner the transfer of the parquet plate from onedevice to a second device for breaking up all joints could be avoided.The counter pressure plate can consist of rubber or can also be formedby a rigid plate with controllable ledges-which can be sunk into theplate.

The method described with reference to FIGS. 6 to 10 for producingsealed mosaic pattern parquet plates which are ready for being laid ismore advantageous than the method explained with reference to FIGS. 2and 3, according to which the individual parquet strips arranged to forma continuous band are ground and sealed, and then the sealing layer isbroken and only afterwards the strips are assembled to a nished parquetplate. By means of the first mentioned method according to which thestrips are rst assembled to a mosaiclike arrangement and the assembledplate is ground and sealed and the strips are subsequently broken up, itis possible to produce parquet oorings in which any unevenness at thejoints between the individual elementary strips and between the squaresformed by groups of strips is avoided.

It is advantageous, for effecting breaking up of the sealing agentlayer, as described with reference to FIGS. 6 to 10, to heat theunderside of the parquet plate, so that when a thermoplastic adhesive orthermoplastic bonding material is used, the bonding tapes slightlysoften 6 and the required extension of the tapes upon relative bendingof the adjacent strips is facilitated.

Instead of using conecting tapes 3 for holding the strips 2 and thesquare groups of strips together, the connection of the assembled stripsand groups of strips could also be made in such manner that a groove iscut into the wood at the underside of the plate along the ends of thestrips at the edges of the plate and along the joints between theadjacent square portions, and an extensible string coated with adhesiveis placed into the grooves. By means of such strings, the strips and thesquare groups of strips are maintained in assembled relation in the samemanner as by means of the extensible tapes.

Obviously it is likewise possible to breakup the sealing layer when,instead of the tapes 3` a bonding means covering the entire area of theunderside of the plate is used, for example a thin sheet of flexible,extensible material extending over the entire surface of the undersideof the plate.

Besides the simple arrangement of strips according to FIG. l, also otherarrangements of elementary blocks or strips are possible, for example asshown in FIGS. 1l and l2. For the stability of the plates, particularadvantages can result by providing parquet strips or ledges 12 or 13forming a frame along the outside of the square or reactangular assemblyof elementary strips.

What is claimed is:

1. A sealed parquet plate ready for laying, composed of individual,elementary elongated parquet strips arranged in edge-to-edge, generallyparalled relation, a continuous sealing agent layer applied on the topwear side of the strips, said layer penetrating said plate and togetheradjacent elongated strips whereby rigid bonding of said individualstrips results due to the formation of the layer which bridges thejoints between adjacent strips, and bonding means of extensible andflexible material applied to the underside of the elementary parquetstrips, said agent layer and said bonding means holding said stripstogether in generally planar relation prior to the laying of the plates,the extensibility of said bonding means being at least twice as great asthe extensibility of said sealing agent layer on the top side of saidelementary strips, whereby breaking of said layer at the joints and thereestablishment of the independence of each of said elementary strips atthe-wear surface while maintaining the integrity of the bonding means isfacilitated to permit the use of hydrous adhesives in securing saidparque plate to a iloor, subfloor and the like.

References Cited UNITED STATES PATENTS 1,43 3,077 10/1922 Hansen 161-1131,778,250 10/ 1930 Elmendorf 144--281 1,819,775 8/1931 Elmendorf137-505.24 2,118,841 5/ 1938 Elmendorf 52--313 2,835,936 5/ 1958Elmendorf 161-38 3,282,010 11/1966 King 52-313 3,279,138 10/ 1966Dittmar 52-390 FOREIGN PATENTS 1,069,350 1954 France.

291,256 1928 Great Britain.

704,707 1954 Great Britain.

965,595 1964 Great Britain. 1,021,062 1966 Great Britain.

HENRY C. SUTHERLAND, Primary Examiner U.S. Cl. X.R.

